The present invention is directed to improvements in solid bowl centrifuges, and more particularly to a method and mechanism for adjustably controlling the liquid level in the centrifuges. More particularly, the improvement relates to a solid bowl centrifuge with openings in an end radial wall and weir elements positioned relative to the openings and movable for restricting the size of the opening to thereby set the liquid level to a predetermined height within the centrifuge drum.
In the process of separation in a solid bowl centrifuge, in order to obtain optimum separating results particularly with slurries that are difficult to separate and to convey, it is expedient to obtain a predetermined exact liquid level in the separating space of the centrifuge and to preserve and maintain that level. An exact setting of the pool height of the liquid in the centrifuge is required to avoid misdischarges when starting up and stopping the centrifuge.
German Patent 37 28 901 discloses a centrifuge construction wherein a weir is employed for controlling the liquid level in a solid bowl centrifuge. In the drum of this worm centrifuge are two weir disks arranged at a distance from one another. Radially extending discharge channels can be closed with an axially movable slide arranged between weir disks. Control chambers are charged with a control agent from outside of the drum by channels connected to the slide.
Although predetermined liquid levels can be set with this known weir construction during operation of the separator drum, the structural arrangement of this known setting mechanism is relatively complicated and is difficult to access for adjustment or repair should that become necessary, since the structure is situated in the interior space of the centrifugal drum. Further, the delivery of the control fluid to the slide which is arranged inside the centrifuge is difficult to control and encounters sealing problems, particularly in the region of a rotary transmission lead-through connection.
It is accordingly an object of the present invention to provide a structure and method of controlling the level of liquid in a solid bowl centrifuge which is not only simple in structural design but particularly which can be monitored and controlled from outside of the drum during separation operation.
A further object of the invention is to provide an improved structure for a solid bowl centrifuge wherein a weir is employed controlling a liquid flow outlet to thereby control the level of separating liquid within the drum.
A further object of the invention is to provide an improved solid bowl separator construction which is capable of more continuous operation without attention and which performs an improved separation operation.